Pure valley current and negative differential resistance in optoelectronic superlattices based on monolayer transition metal dichalcogenides

We investigate the possibility of achieving valley filtering and enhanced negative differential resistance (NDR) in transition metal dichalcogenide (TMD)-based optoelectronic superlattice (SL). The multipeak NDR is predicted to occur in this system, the operation window of which is controlled successively by the resonant tunneling through miniband regime and the Wannier-Stark ladder regime. It is shown that the synergy of the electric and light stimulus can bring the pure valley current and pronounced peak-to-valley current ratio (PVCR). Our findings illustrate the origin of multipeak responses and provide a theoretical basis for designing devices that can generate pure valley current with complex NDR characteristics.